Honeycomb structure and assembly thereof

Abstract

There is disclosed a honeycomb structure ( 1 ) comprising: a plurality of honeycomb segments ( 2 a , 2 b ), bonded into one piece, having a large number of cells ( 6 ) separated from one another by cell walls ( 10 ) and extending through an axial direction. At least one honeycomb segment ( 2 a ) not constituting an outermost peripheral surface ( 23 ) of the honeycomb structure ( 1 ) has a larger average cell wall thickness and a smaller or equal cell density compared with those of at least one honeycomb segment ( 2 b ) constituting the outermost peripheral surface ( 23 ). There is disclosed a honeycomb structure assembly in which a material B having compressive elasticity is disposed in a compressed state on the outermost peripheral surface ( 23 ) of the honeycomb structure ( 1 ) to compression-hold the honeycomb structure ( 1 ) in a metallic container. The honeycomb structure and assembly can prevent deterioration of reactivity, purification efficiency, and regeneration efficiency at the time of use, and can be low in pressure loss and better in durability against breakage by thermal stress.

1. A honeycomb structure comprising a plurality of honeycomb segments bonded into one piece, each segment having a plurality of cells separated from one another by cell walls and extending through an axial direction, wherein at least one of the honeycomb segments which do not constitute an outermost peripheral surface of the honeycomb structure has an average cell wall thickness larger than an average cell wall thickness of each of the honeycomb segments which constitute the outermost peripheral surface, and a cell density that is smaller than or equal to a cell density of said at least one of the honeycomb segments which constitute the outermost peripheral surface. 
   
   
     2. The honeycomb structure according to  claim 1 , wherein a ratio of the cell density of at least one of the honeycomb segments which do not constitute the outermost peripheral surface to a cell density of at least one of the honeycomb segments which constitute the outermost peripheral surface is in a range of 1:1 to 1:6. 
   
   
     3. The honeycomb structure according to  claim 1 , wherein a ratio of the average cell wall thickness in the honeycomb segments which constitute the outermost peripheral surface to the average cell wall thickness in the at least one of the honeycomb segments which do not constitute the outermost peripheral surface is in a range of 0.2 to 0.9. 
   
   
     4. The honeycomb structure according to  claim 2 , wherein a ratio of the average cell wall thickness in the honeycomb segments which constitute the outermost peripheral surface to the average cell wall thickness in the at least one of the honeycomb segments which do not constitute the outermost peripheral surface is in a range of 0.2 to 0.9. 
   
   
     5. The honeycomb structure according to  claim 1 , wherein a sectional area of at least one of the honeycomb segments which do not constitute the outermost peripheral surface is in a range of 9% to 81% of a sectional area of the honeycomb structure. 
   
   
     6. The honeycomb structure according to  claim 4 , wherein a sectional area of at least one of the honeycomb segments which do not constitute the outermost peripheral surface is in a range of 9% to 81% of a sectional area of the honeycomb structure. 
   
   
     7. A honeycomb structure according to  claim 1 , wherein the honeycomb structure is an exhaust gas purification filter of an automobile. 
   
   
     8. The honeycomb structure according to  claim 1 , wherein the honeycomb structure is a filter that traps diesel particulate. 
   
   
     9. The honeycomb structure according to  claim 1 , wherein a material A having compressive elasticity is provided at part or the whole of the space between two adjacent honeycomb segments. 
   
   
     10. The honeycomb structure according to  claim 9 , wherein the material A having compressive elasticity is a ceramic fiber-made mat. 
   
   
     11. The honeycomb structure according to  claim 10 , wherein the ceramic fiber-made mat is a non-intumescent mat mainly composed of an alumina or mullite composition. 
   
   
     12. The honeycomb structure according to  claim 1 , wherein the main component of each honeycomb segment comprises (1) at least one kind of ceramic selected from the group consisting of silicon carbide, silicon nitride, cordierite, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, titania and combinations thereof, and (2) Fe—Cr—Al, nickel, or metallic Si and SiC. 
   
   
     13. A honeycomb structure assembly comprising;
 a honeycomb structure including a plurality of honeycomb segments bonded into one piece, each segment having a plurality of cells separated from one another by cell walls and extending through an axial direction, at least one of the honeycomb segments which do not constitute an outermost peripheral surface of the honeycomb structure having an average cell wall thickness larger than an average cell wall thickness of each of the honeycomb segments which constitute the outermost peripheral surface, and having a cell density smaller than or equal to a cell density of the honeycomb segments which constitute the outermost peripheral surface, 
 a material B disposed in a compressed state on the outermost peripheral surface of the honeycomb structure, and 
 a metallic container, 
 wherein the honeycomb structure is compression-held in the metallic container by the material B. 
 
   
   
     14. The honeycomb structure assembly according to  claim 13 , wherein the material B having compressive elasticity is a ceramic fiber-made mat. 
   
   
     15. The honeycomb structure assembly according to  claim 14 , wherein the ceramic fiber-made mat is a heat-intumescent mat containing vermiculite, or a non-intumescent mat. 
   
   
     16. The honeycomb structure assembly according to  claim 13 , wherein the honeycomb structure assembly is a canned structure obtained by a stuffing method, a tourniquet method, a clamshell method or a swaging method. 
   
   
     17. The honeycomb structure assembly according to  claim 13 , wherein the honeycomb structure assembly is obtained by loading a catalyst on the honeycomb segments and then accommodating the catalyst-loaded honeycomb segments in the metallic container. 
   
   
     18. The honeycomb structure assembly according to  claim 13 , wherein the honeycomb structure assembly is obtained by accommodating the honeycomb segments in the metallic container and then loading a catalyst on the honeycomb segments.